1. Field of the Invention
The present invention relates to a dubbing apparatus and, more particularly, to an apparatus for dubbing signals in which recording information, such as a distinction between a picture field and a picture frame, a track number, the date of shooting, etc. is multiplexed with compound video signals of a still picture.
2. Description of the Prior Art
FIG. 4 illustrates a conventional magnetic recording and reproducing apparatus for recording and reproducing video signals of a still picture. The arrangement is such that, by connecting this apparatus to an identical apparatus, dubbing can be effected from one apparatus to the other.
Namely, if an operation switch 10, consisting of a plurality of switches, is operated to set the mode to a reproduction mode, an analog switch 14 is changed over to the PB side by means of a system controller 12. A signal recorded on a magnetic disc 16 is read by a magnetic head 18.
Concentric tracks are defined on the magnetic disk 16, and composite color video signals of one-field picture and various types of recording information multiplexed therewith are recorded on each track. These various types of information which identifies the recorded image will hereinafter be collectively referred to as ID code.
The read signal is supplied to a recording information separation circuit 22 via a reproducing amplifier 20, where it is separated into a composite color video signal and recording information. The separated recording information is fetched to an output terminal 28 via a differential phase shift keying (DPSK) demodulation circuit 26 and is further supplied to the system controller 12 via a decoder 30, and this recording information being displayed on a display 32. Meanwhile, the composite color video signal is fetched from the recording information separation circuit 22 to an output terminal 34 via a frequency demodulation circuit 24. A synchronizing signal contained in this signal is separated by a synchronizing signal separation circuit 36, and is supplied to a decoder 30 as a timing signal.
Reproduction signals fetched to the output terminals are supplied to another magnetic recording and reproducing apparatus having the same configuration as the one shown in FIG. 4, and dubbing is carried out. To describe this dubbing procedure with reference to FIG. 4, if the operation switch 10 is operated to select the recording mode and the dubbing mode, an analog switch 38 is changed over to the D side by means of the system controller 12, while the analog switch 14 is changed over to the REC side. The above-described recording information is supplied to one input terminal of a synthesizing circuit 44 via an input terminal 40, the analog switch 38, and a DPSK modulation circuit 42. Meanwhile, the above-described reproduced video signal is supplied to the other input terminal of the synthesizing circuit 44 via an input terminal 46 and a frequency modulation circuit 48. In addition, a synchronizing signal contained in the video signal is supplied to the DPSK modulation circuit 42 as a timing signal. The output of the synchronization circuit 44 is supplied to the magnetic head 18 via a recording amplifier 52 and the analog switch 14, and is recorded on the magnetic disk 16.
When normal recording is to be effected, the operation switch 10 is operated, and recording information is input to the system controller 12 while it is being confirmed through the display 32. This recording information is supplied to the synthesization circuit 44 via the encoder 54, the analog switch 38, and the DPSK modulation circuit 42 with the synchronizing signal from the synchronizing signal separation circuit 36 serving as a timing signal, and is synthesized (frequency division multiplexed) with the signal in which the composite color video signal supplied from the input terminal 46 is subjected to frequency modulation. The subsequent procedure is the same as the case of the above-described dubbing.
The format (standard format) of recording information in an electronic still camera is shown in FIG. 3. In the drawing, nH denotes a n-number of horizontal synchronization pulses, and the upper side of / is the case where recording is carried out in odd-numbered fields, while the lower side of / is the case where recording is carried out in even-numbered fields. Switching point SP constitutes a reference position of the rotation of the magnetic disk 16, and is detected each time the magnetic disk 16 undergoes one rotation. The rotation of the magnetic disk 16 is controlled in such a manner that the interval between the switching point SP and a vertical synchronizing signal VSYNC becomes 7H. Recording information (ID code) includes that of a distinction between the field picture and the frame picture, a distinction between an outer track and an inner track in the case of a frame picture, the number of a track on which the picture is recorded, the date of shooting, and a user's area where the user can record information at his disposal. The recording density of recording information is one bit with respect to 4H. However, the user's area may be 2H/1 bit.
However, since the recording information is dubbed as it is together with video signals, if the track number of the magnetic disk from which dubbing is effected is different from that of the magnetic disk to which dubbing is effected, dubbing is effected on a track whose track number is different that of the recording information.
In addition, if, with respect to the frame picture constituted two fields, dubbing is effected by using only one field as the field picture, the recording information is recorded as the frame picture. Therefore, if this is reproduced, it is reproduced as the frame picture, with the result that the reproduced picture is disturbed.
Furthermore, although there are cases where it is desirable to automatically change the contents of the user's area for the purpose of controlling the dubbing quality each time dubbing is conducted, it is impossible to meet such demand.